High-strength heat-resistant insulating material and preparation method thereof

Abstract

The invention relates to a high-strength heat-resistant insulating material and a preparation method thereof, and belongs to the field of polymer materials for electric wires and cables. The preparation method comprises the following steps: 1, adding low-density polyethylene resin, an antioxidant 1010, an antioxidant 168 and 10 # white oil into a high-speed mixer, and uniformly mixing; 2, adding terphenyltrimethylsilane and dicumyl peroxide into a container, heating to 90 DEG C, and keeping the temperature until the terphenyltrimethylsilane and dicumyl peroxide are completely liquid; (3) adding the materials mixed in the step (1) into a hopper of a double-screw extrusion granulator, adding the solution mixed in the step (2) into a liquid metering pump connected with three areas of the double-screw extrusion granulator, keeping the temperature at 90 DEG C, and then extruding and granulating; the high-strength heat-resistant insulating material is obtained. The prepared high-strength heat-resistant insulating material is mainly used for insulation of electric wires and cables, replaces a traditional crosslinked polyethylene material, is a thermoplastic material and can be recycled.

Description

Technical Field

[0001] The invention relates to a high-strength heat-resistant insulating material and a preparation method thereof, belonging to the technical field of polymer materials for wires and cables. Background Art

[0002] At present, cross-linked polyethylene is widely used as an insulating material in wires and cables. It is the main cross-linkable insulating material used in power cables. However, cross-linked polyethylene generally adopts chemical cross-linking, and cross-linking needs to be carried out under high temperature and high pressure conditions. The production energy consumption is high, the cross-linking equipment is complex and expensive, and by-product gas is discharged after cross-linking, which is not conducive to carbon reduction and emission reduction. In addition, it is not easy to recycle and reuse after cross-linking, and the material is not easy to degrade.

[0003] In order to overcome the above shortcomings of the current cross-linked polyethylene insulation materials, it is necessary to design and develop a new generation of modified polyethylene insulation materials, which not only meet the performance of general chemical cross-linked polyethylene materials, but also have higher advantages in heat resistance, strength, thermal deformation, thermal expansion performance, etc.

[0004] This new generation of modified polyethylene insulation material is a non-cross-linked material and a thermoplastic material. It can be reused and has the characteristics of low production energy consumption and easy recycling. It is highly environmentally friendly and economical. Summary of the Invention

[0005] The purpose of the present invention is to provide a high-strength heat-resistant insulating material and a preparation method thereof in view of the above-mentioned problems existing in existing cross-linked polyethylene insulating materials.

[0006] To achieve the above object, the technical solution adopted by the present invention is:

[0007] A method for preparing a high-strength heat-resistant insulating material comprises the following steps:

[0008] first step:

[0009] Take low-density polyethylene resin (LDPE), antioxidant 1010, antioxidant 168, and 10# white oil and add them into a high-speed mixer. Mix them thoroughly for 3-5 minutes at room temperature until they are evenly mixed.

[0010] Step 2:

[0011] Add terphenyltrimethylsilane (TMDSB) and dicumyl peroxide (DCP) into a container, raise the temperature to 90°C and maintain it until terphenyltrimethylsilane and dicumyl peroxide are completely liquid;

[0012] Step 3:

[0013] The mixed material in the first step is added into the hopper of a twin-screw extruder for granulation, and a liquid metering pump is installed in the middle of the twin-screw extruder;

[0014] Add the liquid mixed in the second step to the liquid metering pump and maintain it at 90°C. The liquid metering pump injects the liquid into the mixing area of ​​the twin-screw extruder according to the extrusion speed.

[0015] Step 4:

[0016] The granules produced by extrusion granulation in the third step are packaged and stored to obtain the product of the present invention.

[0017] Furthermore, in the first step, the mass ratio of low-density polyethylene resin, antioxidant 1010, antioxidant 168, and 10# white oil is: 80-100: 0.3-0.5: 0.3-0.5: 0.05-0.08.

[0018] Furthermore, the mixing process in the first step is: first add low-density polyethylene resin, start the mixer, then add 10# white oil, continue mixing for 1 minute, and then add antioxidant 1010 and antioxidant 168.

[0019] Furthermore, in the second step, the mass ratio of terphenyltrimethylsilane to dicumyl peroxide is 80-95:4-5.

[0020] Furthermore, in the third step, the mass ratio of the material mixed in the first step to the liquid mixed in the second step is 98.5:1.5, and the injection volume of the liquid metering pump during the extrusion process is set according to this mass ratio.

[0021] Furthermore, in the third step, the process temperature of the twin-screw extruder is: 130±2°C in zone 1, 145±2°C in zone 2, 160±2°C in zone 3, 185±2°C in zone 4, 210±2°C in zone 5, 210±2°C in zone 6, and 210±2°C in the die head.

[0022] Furthermore, in the third step, the liquid metering pump is set in the three zones of the twin-screw extruder. Among them, the first, second and third zones are conveying zones, the fourth zone is the initiation zone, the fifth and sixth zones are reaction zones, and the die head is the extrusion granulation zone. This process adopts water ring extrusion granulation.

[0023] Furthermore, the high-strength heat-resistant insulating material prepared by the preparation method is used in wires and cables.

[0024] Description of the main raw materials used in this invention:

[0025] Low-density polyethylene resin (LDPE): 190°C, 2.16 kg, melt flow rate 2.0 ± 0.2 g / 10 min;

[0026] Antioxidant 1010: white powder, antioxidant;

[0027] Antioxidant 168: white powder, antioxidant;

[0028] 10# white oil: transparent liquid, mixing additive;

[0029] Triphenyltrimethylsilane (TMDSB): powder or crystal, reactive monomer;

[0030] Dicumyl peroxide (DCP): white crystalline powder, reaction initiator.

[0031] Compared with the prior art, the present invention has the following beneficial effects:

[0032] 1. In the preparation method of the present invention, a mixture of terphenyltrimethylsilane and dicumyl peroxide is mixed with the resin material in the third zone of a twin-screw extruder granulator via a liquid metering pump. This is because terphenyltrimethylsilane and dicumyl peroxide melt into a liquid at temperatures above 40°C, resulting in a very smooth surface. If terphenyltrimethylsilane and dicumyl peroxide are directly mixed with the material, the material cannot be advanced in the front section of the extruder and will slip on the screw. This mixing method allows for more accurate metering, as terphenyltrimethylsilane and dicumyl peroxide require precise metering. Direct mixing would result in an inaccurate ratio of polyethylene to terphenyltrimethylsilane and dicumyl peroxide. Because terphenyltrimethylsilane and dicumyl peroxide are relatively volatile, injecting terphenyltrimethylsilane and dicumyl peroxide directly into the mixing zone allows for a direct reaction, preventing loss of terphenyltrimethylsilane and dicumyl peroxide and improving raw material utilization.

[0033] 2. The present invention prepares a high-strength heat-resistant insulating material, which is mainly used for the insulation of wires and cables, replacing traditional cross-linked polyethylene materials. The product of the present invention is a thermoplastic material that can be recycled and reused. The product introduces a polyphenyl ring group side group into the polyethylene molecular chain. The side group contains 3 benzene rings and is chemically bonded to the main chain macromolecule. The side group is a rigid structure. The present invention mainly improves the performance of the material in terms of heat resistance, strength, thermal deformation, and thermal expansion coefficient. The polymer main chain of the product of the present invention is a polyethylene macromolecular flexible chain, and the side group is a rigid unit containing three benzene rings. The side group is a rigid structure with liquid crystal properties, which makes the molecular chain of the entire macromolecular polymer have the properties of a liquid crystal polymer, greatly improving the performance of the insulating material.

[0034] The specific reaction process of the present invention is:

[0035] Triphenyltrimethylsilane (TMDSB) undergoes a grafting reaction with low-density polyethylene macromolecules under the action of the initiator diisopropylbenzene peroxide (DCP) to form a macromolecular polymer with the following structure.

[0036] DETAILED DESCRIPTION

[0037] The technical solutions and effects of the present invention are further described below in conjunction with specific embodiments, but the protection scope of the present invention is not limited thereto.

[0038] Example 1

[0039] A method for preparing a high-strength heat-resistant insulating material comprises the following steps:

[0040] first step:

[0041] Take 80 kg of low-density polyethylene resin and add it to a high-speed mixer. Start the mixer, then add 0.05 kg of 10# white oil and mix for 1 minute. Then add 0.3 kg of antioxidant 1010 and 0.3 kg of antioxidant 168 and continue mixing for 4 minutes until the mixture is evenly mixed.

[0042] Step 2:

[0043] 80 kg of terphenyltrimethylsilane and 4 kg of dicumyl peroxide were added to a container, and the temperature was raised to 90° C. and maintained until the terphenyltrimethylsilane and dicumyl peroxide were completely liquid.

[0044] Step 3:

[0045] Add 98.5 kg of the material mixed in the first step into the hopper of the twin-screw extruder granulator, and add 1.5 kg of the liquid mixed in the second step into the liquid metering pump connected to the three zones of the twin-screw extruder granulator. Maintain the temperature at 90 ° C. According to the mass of the material mixed in the first step and the liquid mixed in the second step, control the extrusion speed and the injection speed of the liquid metering pump, and then extrude and granulate.

[0046] The process temperature of the twin-screw extruder granulator is: zone 1 130±2℃, zone 2 145±2℃, zone 3 160±2℃, zone 4 185±2℃, zone 5 210±2℃, zone 6 210±2℃, and die head 210±2℃.

[0047] Step 4:

[0048] The granules produced by extrusion granulation in the third step are packaged and stored to obtain the product of the present invention.

[0049] Example 2

[0050] Same as Example 1, except that:

[0051] first step:

[0052] Take 100 kg of low-density polyethylene resin, 0.5 kg of antioxidant 1010, 0.5 kg of antioxidant 168, and 0.08 kg of 10# white oil and add them into a high-speed mixer.

[0053] Step 2:

[0054] 95 kg of terphenyltrimethylsilane and 5 kg of dicumyl peroxide were added to a container.

[0055] Example 3

[0056] Same as Example 1, except that:

[0057] first step:

[0058] Take 85 kg of low-density polyethylene resin, 0.4 kg of antioxidant 1010, 0.4 kg of antioxidant 168, and 0.06 kg of 10# white oil and add them into a high-speed mixer.

[0059] Step 2:

[0060] 95 kg of terphenyltrimethylsilane and 4.5 kg of dicumyl peroxide were added to a container.

[0061] The following properties are measured according to the provisions of JB / T10437-2024 "Cross-linked polyethylene insulation materials for wires and cables" or the referenced standards.

[0062] Table 1 Performance comparison between cross-linked polyethylene insulation material and the product of the present invention

[0063]

[0064] The cross-linked polyethylene insulation material is taken from Hebei Hunter Cable Material Co., Ltd., 10KV and below cross-linked polyethylene insulation material, YJ02-10.

[0065] As can be seen from the table above, in addition to meeting national standards, the patented product of this invention has much higher heat deformation temperature and maximum operating temperature than cross-linked polyethylene. In terms of thermal expansion coefficient, it is two orders of magnitude lower than cross-linked polyethylene.

[0066] While embodiments of the present invention have been shown and described, it will be appreciated by those skilled in the art that various changes, modifications, substitutions, and variations may be made to these embodiments without departing from the principles and spirit of the invention, and that the scope of the invention is defined by the appended claims and their equivalents.

Claims

1. A method for preparing a high-strength heat-resistant insulating material, characterized in that: The preparation method comprises the following steps: first step: Add low-density polyethylene resin, antioxidant 1010, antioxidant 168, and 10# white oil into a high-speed mixer and mix thoroughly for 3-5 minutes at room temperature until evenly mixed. Step 2: Add terphenyltrimethylsilane and dicumyl peroxide into a container, raise the temperature to 90°C and maintain it until the terphenyltrimethylsilane and dicumyl peroxide are completely liquid; Step 3: The mixed material in the first step is added into the hopper of a twin-screw extruder for granulation, and a liquid metering pump is installed in the middle of the twin-screw extruder; Add the liquid mixed in the second step to the liquid metering pump and maintain it at 90°C. The liquid metering pump injects the liquid into the mixing area of ​​the twin-screw extruder according to the extrusion speed. Step 4: The granules extruded and granulated in the third step are packaged and stored to obtain high-strength heat-resistant insulating materials.

2. The method for preparing a high-strength heat-resistant insulating material according to claim 1, characterized in that: In the first step, the mass ratio of low-density polyethylene resin, antioxidant 1010, antioxidant 168, and 10# white oil is: 80-100: 0.3-0.5: 0.3-0.5: 0.05-0.

08.

3. The method for preparing a high-strength heat-resistant insulating material according to claim 1, characterized in that: The mixing process in the first step is: first add low-density polyethylene resin, start the mixer, then add 10# white oil, continue mixing for 1 minute, and then add antioxidant 1010 and antioxidant 168.

4. The method for preparing a high-strength heat-resistant insulating material according to claim 1, wherein: In the second step, the mass ratio of terphenyltrimethylsilane to dicumyl peroxide is 80-95:4-5.

5. The method for preparing a high-strength heat-resistant insulating material according to claim 1, characterized in that: In the third step, the mass ratio of the material mixed in the first step to the liquid mixed in the second step is 98.5:1.5, and the injection volume of the liquid metering pump during the extrusion process is set according to this mass ratio.

6. The method for preparing a high-strength heat-resistant insulating material according to claim 1, characterized in that: In the third step, the process temperature of the twin-screw extruder is: 130±2°C in zone 1, 145±2°C in zone 2, 160±2°C in zone 3, 185±2°C in zone 4, 210±2°C in zone 5, 210±2°C in zone 6, and 210±2°C in the die head.

7. The method for preparing a high-strength heat-resistant insulating material according to claim 6, characterized in that: In the third step, the liquid metering pump is arranged in the third zone of the twin-screw extruder granulator.

8. The method for preparing a high-strength heat-resistant insulating material according to claim 1, characterized in that: The high-strength heat-resistant insulating material prepared by the preparation method is used in wires and cables.

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